Suspended work platform with an integrated rescue system and a method for rescuing a worker

ABSTRACT

A suspended work platform with an integrated rescue system and a method for rescuing a worker is used to quickly rescue workers from an elevated position. The system incorporates a work hoist and a rescue device cooperating with a platform rope. The work hoist is attached to the work platform. A worker changes the elevation of the work platform by operating a work input device of a work hoist control system. The rescue device cooperates with the platform rope and is attached above the work platform to a tie-off location. A rescuer operates the rescue device to perform a rescue of the worker when necessary. The rescue system may also include an independent fall arrest system having a descent control system with a fall arrest rope attached to the worker and to the tie-off location.

TECHNICAL FIELD

The instant invention relates to suspended work platform hoist system, and, more particularly, relates to a system and method having a pre-rigged hoisting system for quickly rescuing a worker trapped at an elevated position on a suspended work platform.

BACKGROUND OF THE INVENTION

Suspension type work platforms, also commonly referred to as access platforms or free-hanging scaffolds, are well-known in the art. The work platforms may be used to support workers along the side of a structure in connection with window washing, painting, or repair work on high-rise buildings or “sky scrappers.” These types of platforms are also used to suspend workers within large pressure vessels, such as boilers used in the electrical power generation industry, to accomplish periodic maintenance and cleaning that are often required to extend the service life of the boilers.

In either case, multi-worker platforms are typically powered by a hoist at each end of the platform. The hoists raise and lower the platform on a suspension wire, or platform rope, in conjunction with each hoist. The hoists are generally very simple machines including an electric motor, a gearbox, and a traction mechanism that grips the wire or rope. Also, sometimes, it is more cost effective and timely to use a single worker platform, or bosun's chair, to perform repair, maintenance, or cleaning operations. These single worker systems are also operated by hoists in cooperation with the platform rope. As with any suspended platform, safety of the worker is essential both from a fall perspective and from a rescue perspective. Fall prevention equipment must be used, and plans and equipment for rescuing stranded or injured workers must be in place.

Boilers, tanks, and other vessels, such as silos, storage bins, hoppers, vaults, and pits, are used in the containment of various substances. In the safety industry, these containment systems are known as confined spaces. Generally confined spaces are those where a worker may bodily enter to perform work, has limited entry and exit means, and is not designed for continuous worker occupancy. Unlike along side a building, a confined space may contain trapped residual hazardous gases and liquids. By itself, the enclosed nature of the vessel may create an environment that is dangerous to the worker.

Once designated a confined space, special precautions must be taken in order to rescue the worker from the space should a dangerous situation threaten the worker's health. As a part of those precautions, rescue equipment and rescuers must be available at a moments notice. If an emergency does occur, time may be of the essence. To complicate the rescue, the presence of hazardous substances may threaten the life of the rescuer. Therefore, workers on a suspension platform within a vessel may be exposed to hazards created by the enclosed nature of the vessel and by the height of the work platform. If the rescuers have to enter the vessel to rescue the worker, the rescuers may also be risking their lives.

What has been missing in the art has been a system by which workers may rescue themselves, allows rescuers to perform a rescue of a worker from a safe location, and allows a rescuer to perform a rescue without entry into a confined space. Further, the art has been missing a system which is capable of rescuing the worker within minutes of the emergency.

SUMMARY OF INVENTION

In its most general configuration, the present invention advances the state of the art with a variety of new capabilities and overcomes many of the shortcomings of prior devices in new and novel ways. In its most general sense, the present invention overcomes the shortcomings and limitations of the prior art in any of a number of generally effective configurations. The instant invention demonstrates such capabilities and overcomes many of the shortcomings of prior methods in new and novel ways.

In one embodiment of the instant invention, a suspended work platform with an integrated rescue system includes a work platform suspended from a tie-off point. The work platform is positioned along one surface of a structure such that a worker may complete various assigned tasks. The tie-off point is above the work platform and a fall surface is below the work platform. A platform rope suspends the work platform from a work hoist and is engaged by a rescue device at the top portion of the structure. The system fully addresses the rescue of a worker stranded or injured on the work platform at an elevated height.

The work hoist is attached to the work platform. The work hoist has a work hoist motor, a work hoist traction mechanism designed to cooperate with the platform rope, and a work hoist gear box for transferring power from the work hoist motor to the work hoist traction mechanism. In an embodiment of the instant invention, the work hoist has a work hoist controlled descent device. The work hoist controlled descent device controls the passage of the platform rope through the work hoist allowing the work platform to descend toward the fall surface.

Operation of the work hoist is accomplished with a work hoist control system which is in operative communication with a worker input device. The worker input device and the work hoist control system may be in operative communication with the work hoist. The worker manipulates the worker input device to have the work hoist ascend or descend the platform rope.

The rescue device has a rescue traction mechanism designed to cooperate with the platform rope. The rescue device also has a rescue traction brake designed to engage the rescue traction mechanism and includes a rescue over-speed brake for stopping uncontrolled passage of the platform rope through the rescue device. A rescue controlled descent device releasably cooperates with the rescue traction brake permitting a safe descent of the work platform.

Typically, during normal day-to-day operation of the system, the rescue device is not operated. The rescue device merely locks the platform rope in position with the rescue traction brake and the rescue over-speed brake. In the event that the work hoist becomes inoperable, whether through a power loss, a mechanical failure in the work hoist, a problem with the platform rope, or incapacitation of the worker, a rescuer does not have to rig a rescue system to bring the stranded worker to safety. With the system, the rescuer operates the integrated rescue device to raise or lower the affected worker.

The platform rope has a maximum extension length that is determined by fully extending the platform rope. The maximum extension length of the platform rope exceeds the working elevation range. In one particular embodiment, the maximum extension length of the platform rope may be approximately at least 150% of the working elevation range. In another related embodiment, the maximum extension length of the platform rope is at least 190% of the working elevation range to allow easier access to the work platform by emergency personnel. In another embodiment of the present invention, the excess platform rope extends through the rescue device into a wire winder.

In another embodiment of the instant invention, the rescue device is a rescue hoist. The rescue hoist may have a rescue hoist motor and a rescue hoist gear box for transferring power from the rescue hoist motor to the rescue traction mechanism. The system may have a rescue hoist control system having a rescuer input device.

In an embodiment of the instant invention, the rescue hoist control system is in operative communication with the rescue hoist and the work hoist. The rescuer input device controls the rescue hoist motor to extend and retract the platform rope. In another embodiment of the instant invention, the rescuer input device includes a stop button and a directional control.

In another embodiment of the instant invention, the system is rigged within an enclosed structure or a confined space. The platform rope extends from the rescue hoist into the structure to the work platform. The rescue hoists are attached to the tie-off point located above the work hoists. The position of the rescue hoist permits the rescuer to access and operate the rescue hoist without entering the structure or confined space.

In another embodiment of the instant invention, an independent fall arrest system is another safety mechanism for preventing the worker from falling and for providing a means for the rescuer to quickly lower the worker to safety. The independent fall arrest system has a fall arrest rope and a fall arrest device combined with a descent control system.

In one embodiment, the method of rescuing a worker with the rescue device involves raising or lowering the stranded worker by (a) resetting the rescue over-speed brake, (b) disengaging the traction brake and either by (c) manipulating the lever on the rescue device to raise the worker to the top of the building, or (d) operating the rescue controlled descent device to lower the worker to the fall surface.

In one embodiment, the method of rescuing a worker with the rescue hoist involves (a) engaging the work hoist lockout to lockout the work hoist, (b) engaging the power supply tag-out mechanism to allow the rescue hoist control system and the rescue hoist to receive power, (c) resetting the rescue over-speed brake, and (d) disengaging the stop button. The rescuer operates the rescue hoist by (e) operating the directional control which disengages the rescue brake, or by (f) operating the rescue controlled descent device. In another, more dire, situation, where the worker is suspended by the independent fall arrest system, the rescuer may lower the worker by operating the fall arrest device to raise or lower the worker in a controlled fashion.

These variations, modifications, alternatives, and alterations of the various preferred embodiments may be used alone or in combination with one another, as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Without limiting the scope of the present invention as claimed below and referring now to the drawings and figures:

FIG. 1 is a schematic of an embodiment of the suspended work platform with an integrated rescue system of the present invention with a work platform and a rescue device, not to scale;

FIG. 2 is a schematic of an embodiment of the suspended work platform with an integrated rescue system of the present invention with the work platform and a rescue hoist, not to scale;

FIG. 3 is an elevation view of an embodiment of a work hoist and a work hoist control system with a work platform, not to scale;

FIG. 4 is an elevation view of an embodiment of the rescue hoist and a rescue hoist control system, not to scale;

FIG. 5 is a schematic of an embodiment showing connectivity between the rescue hoist, the work hoist, the work hoist control system, and the rescue hoist control system, not to scale; and

FIG. 6 is an elevation view of an embodiment of the rescue device, not to scale.

DETAILED DESCRIPTION OF THE INVENTION

The suspended work platform with an integrated rescue system (50) of the instant invention enables a significant advance in the state of the art. The preferred embodiments of the device accomplish this by new and novel arrangements of elements and methods that are configured in unique and novel ways and which demonstrate previously unavailable but preferred and desirable capabilities. The detailed description set forth below in connection with the drawings is intended merely as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

Referring now to FIG. 1, in one embodiment of the instant invention, a suspended work platform with an integrated rescue system (50) includes a work platform (100) suspended from a tie-off point (20) such that a worker may complete various tasks, such as, by way of example and not limitation, painting, cleaning, inspection, or welding of a structure (10). As seen in FIG. 1, the tie-off point (20) is above the work platform (100), and a fall surface (30) is below the work platform (100). A work hoist (200) is attached to the work platform (100). A platform rope (300) cooperates with the work hoist (200). The platform rope (300) extends up to, and is engaged by, a rescue device (400) attached to the tie-off point (20). By way of example and not limitation, the platform rope (300) may be metal wire or braided cable commonly used in rigging. Thus, as seen in FIG. 1, the tie-off point (20) suspends the rescue device (400), the platform rope (300), the work hoist (200), and the work platform (100). As one skilled in the art will observe, the rescue device (400) may not be suspended from the tie-off point (20) but rather the rescue device (400) may be secured to a top surface of tie-off point (20). Furthermore, the structure (10) may be a building having multiple floors; a silo, boiler, or other industrial vessel; a pit or open tank; or any structure or confined space having a height that requires specialized rigging to access its external, and as discussed later, its internal surfaces.

One skilled in the art will also observe that the work platform (100) may be a work cage, as seen in FIG. 1, a modular platform which may support multiple workers, as seen in FIG. 2, or bosun chair for suspending one worker along the structure (10). The fall surface (30) is any surface that exists below the work platform (100) that would stop the work platform's (100) motion downward, or any surface that would stop an object that fell from the work platform (100), such as a concrete sidewalk, a ledge of the structure that juts out under the work platform (100), or even another work platform (100).

Finally, as seen in FIGS. 1 and 2, the tie-off point (20) may be any number of rigging devices, such as, telescopic roof beams, mobile roof beams, cornice hooks (with or without stand off devices), and parapet clamps, to name only a few. Further, in many embodiments, the tie-off point (20) may simply be the point at which the rescue device (400) is secured to a stationary object. In one embodiment of the invention, the tie-off point (20) is electrically insulated to allow the worker to safely weld from the work platform (100). The tie-off point (20) may also be outside a confined space, as discussed in detail later. The components of the system (50) themselves, as well as their arrangement, provide features unknown in the art of suspension work platform safety. By way of example and not limitation, the system (50) addresses the rescue of a worker stranded or injured on the work platform at an elevated height, such as in the event of a power failure, an injury leaving the worker incapacitated, a disabled work hoist (200), or even if the platform rope (300) fails catastrophically. Moreover, the rescue of a stranded worker proceeds in a safe manner, does not require additional rigging, permits non-entry rescue in certain situations, requires minimal training, and where the occasion requires, particularly in life or death situations, proceeds quickly. Now the individual components of the system (50) will be described in greater detail.

The work hoist (200), as seen in FIG. 3, is attached to the work platform (100). The work hoist (200) has a work hoist motor (210), a work hoist traction mechanism (230) designed to cooperate with the platform rope (300), and a work hoist gear box (220) for transferring power from the work hoist motor (210) to the work hoist traction mechanism (230). The work hoist (200) may utilize an electric, pneumatic, or hydraulic powered work hoist motor (210), such as any one of the hoists available via Sky Climber, LLC. of Stone Mountain, Ga.

The work hoist traction mechanism (230) discussed herein is designed to grip the platform rope (300) and may be of the solid sheave type, which are known in the art. Further, the work hoist gear box (220) may be a planetary and worm gear system designed to reduce the rotational speed of the work hoist motor (210) to a usable speed. One with skill in the art will appreciate that other gear systems may be incorporated in the work hoist gear box (220). In another embodiment of the instant invention, the work hoist (200) is equipped with a work hoist brake (240) that releasably engages the work hoist traction mechanism (230). In yet another embodiment of the instant invention, the work hoist (200) has a work hoist over-speed brake (250), such as the Sky Lock II and Sky Lock III available via Sky Climber, LLC. The work hoist over-speed brake (250) prevents uncontrolled withdrawal of the platform rope (300) through the work hoist (200). While the present description focuses on a single rope (300) per work hoist (200), one with skill in the art will appreciate that the present invention also covers applications that require multiple ropes for each hoist, as is common in Europe.

In an embodiment of the instant invention, as seen in FIG. 3, the work hoist (200) has a work hoist controlled descent device (260). The work hoist controlled descent device (260) controls the passage of the platform rope (300) through the work hoist (200). Therefore, in the event of a power failure where the work hoist (200) is rendered inoperable, the worker may operate the work hoist controlled descent device (260) to allow the platform rope (300) to pass through the work hoist traction mechanism (230) in a controlled manner and causing the work platform (100) to descend toward the fall surface (30). In other words, the work hoist controlled descent device (260) may be a non-powered device that merely allows gravity to pull the work platform (100) towards the earth in a controlled fashion.

Operation of the work hoist (200) is accomplished with a work hoist control system (700), as seen in FIG. 3. The work hoist control system (700) is in operative communication with a worker input device (710). Operative communication means the components are functionally linked and cooperate, by way of example and not limitation, operative communication may include electrical, wireless, pneumatic, and hydraulic communication or combinations thereof. Furthermore, the worker input device (710) and the work hoist control system (700) may be in operative communication with the work hoist (200). The worker manipulates the worker input device (710) to have the work hoist (200) ascend or descend on the platform rope (300). The work hoist control system (700) may incorporate functions other than merely accepting instructions to raise or lower the work platform (100). Various embodiments of the present invention may call for the addition of input devices associated with the work hoist control system (700). Such additional input devices may include (a) approach mode enable/disable, (b) adjustable approach velocity setpoint, (c) work mode enable/disable, (d) adjustable approach velocity setpoint, (e) adjustable acceleration period setpoint, and (f) hoist master/slave selector to identify which work hoist on a two work hoist platform generates the control power or control signal and which merely receives the power or control signal and responds accordingly.

Generally the work hoist control system (700) is a control box, which has numerous buttons and switches, or worker input devices (710), for controlling the suspended work platform (100). In some applications the work hoist control system (700) includes a pendant so that the worker does not need to be located at the work hoist control system (700) to control the movement of the work platform (100). In other words, the worker input device (710) may be at least one control switch, button, or toggle located on a fixed central control box or it may be all, or some, of those same devices located on a movable pendent. Generally, the worker input device (710) will include up/down hold-to-run switches, hoist selector switches (in the case of multiple hoists attached to the work platform), and an emergency stop button. In addition the work hoist control system (700) may call for the addition of input devices and motor control devices to facilitate ease-of-use for the worker and for improving the safety and reliability of the work hoist (200). Such input devices and motor control devices may include (a) approach mode enable/disable, (b) adjustable approach velocity setpoint, (c) work mode enable/disable, (d) adjustable approach velocity setpoint, (e) adjustable acceleration period setpoint, and (f) hoist master/slave selector to identify which hoist generates a control power or control signal and which hoist merely receives the power or control signal and responds accordingly. The work hoist control system (700) and/or the worker input device (710) may incorporate a LCD screen to view diagnostics and setpoints. Further, the LCD screen may be a touch-screen input system. As previously mentioned, the rescue device (400) cooperates with the platform rope (300) and is attached to the tie-off point (20).

The rescue device (400) may utilize electrical, pneumatic, hydraulic power, or the rescue device (400) may be non-powered. By way of example and not limitation, the rescue device (400) may be any one of a number of manual ratcheting devices such a comealong as seen in FIG. 6, or a manually powered winch or similar device. The non-powered rescue device (400) may have a rescue traction mechanism (430), such as a pawl in cooperation with a ratchet. As seen in FIG. 6, the rescue device (400) cooperates with the platform rope (300). In one embodiment, the rescue device (400) may be capable of raising and lowering the work platform (100) by retracting or extending the platform rope (300) in a controlled manner. In another embodiment, the rescue device (400) is only capable of lowering the work platform (100) in a controlled manner.

Typically, during normal day-to-day operation of the system, the rescue device (400) is not operated. That is, in day-to-day operation of the system (50) the rescue device (400), as seen in FIGS. 1 and 6, merely locks the platform rope (300) in position to suspend the work platform (100). Locking the platform rope may be accomplished by engaging a rescue traction brake (440) and a rescue over-speed brake (450). The rescue traction brake (440) and the over-speed brake (450) are individual redundant safeties designed to prevent the platform rope (300) from being unintentionally withdrawn from the rescue device (400), possibly causing the work platform (100) to fall and thus placing the worker in great peril. In day-to-day operations, the worker adjusts the work platform (100) elevation by operating the worker input device (710) to activate the work hoist (200). By way of example and not limitation, the rescue device (400) may be any one of a variety of cable winch hoists that have a manually powered sheave that grips the platform rope (300). In the event that the work hoist (200) becomes inoperable, whether through a power loss, a mechanical failure in the work hoist (200), a problem with the platform rope (300), or incapacitation of the worker, a rescuer does not have to rig a rescue system to bring the stranded worker to safety. With the present system (50), the rescuer operates the rescue device (400) to raise or lower the work platform (100), even if the work hoist (200) is inoperable or the worker is incapacitated. As seen in FIG. 1, the rescuer may raise or lower the worker to a safe location depending on how the system (50) is rigged on the structure, and other factors, such as, the closest distance to safety, availability of additional rescue personnel, and condition of the worker. In general, the safe location is anywhere the worker is not in danger. By way of example, and not limitation, the safe location may be on the roof of the building or structure, on the ground, or outside of the boiler.

With continued reference to FIG. 1, in an embodiment of the instant invention, the work platform (100) has a highest working elevation (110) where it is prevented from ascending further by the rescue device (400). However, the worker is unable to safely exit the work platform (100) at the highest working elevation (110). For example, this situation may exist when the system (50) is rigged to the top of a sky-scrapper and the work platform (100) is just out of reach of a top edge of the building. At the other end, the work platform (100) has a fall surface exit elevation (120) where the work platform (100) is prevented from being lowered further by the fall surface (30). As seen in FIGS. 1 and 2, a working elevation range (130) is the difference between the highest working elevation (110) and the fall surface exit elevation (120). The worker may position the work platform (100) anywhere within the working elevation range (130) by moving the work hoist (200) along the platform rope (300).

While the platform rope (300) generally extends to near the fall surface (30), so that the work platform (100) may traverse the entire working elevation range (130), in one embodiment of the instant invention, the platform rope (300) has a maximum extension length that exceeds the working elevation range (130). The maximum extension length is determined by fully extending the platform rope (300) to where it may not be extended any further without being released from the rescue device (400) and the rescue over-speed brake (450). In one particular embodiment, if the work platform (100) must be lowered to safety from a position closer to the highest working elevation (110) than to the fall surface exit elevation (120), the maximum extension length of the platform rope (300) should be at least approximately 150% of the working elevation range (130). In other words, the platform rope (300) should be long enough to position the work platform (100) near the fall surface (30) from positions near the highest working elevation (110). Emergency personnel may then access the work platform (100) or the worker can exit the work platform (100) without fear of injury. In another related embodiment, the maximum extension length of the platform rope (300) is at least 190% of the working elevation range (130) to provide a greater range of motion and allow easier access to the work platform (100) by emergency personnel. By way of example, and not limitation, if the work platform (100) is positioned near the top of the structure (10), such that the worker is not able to climb off the work platform (100) onto the structure (10), and the platform wire (300) jams in the work hoist (200), then, to be able to lower the work platform (100) to the fall surface (30), the platform rope (300) must be long enough for the work platform (100) to reach the fall surface (30).

In another embodiment of the present invention, as seen in FIG. 2, the platform rope (300) extends from a wire winder (500). The wire winder (500) gathers or feeds-out the platform rope (300) in the event that the rescue device (400) is used to raise or lower the work platform (100) and prevents the platform rope (300) from kinking, snagging on external objects, or becoming tangled. In one embodiment of the instant invention, the rescue device (400) may be a non-powered, or in other words, gravity-activated device only capable of lowering the work platform (100).

In another embodiment of the instant invention, as seen in FIGS. 2 and 4, the rescue device (400) is a rescue hoist (402). Similar to the work hoist (200), the rescue hoist (402) may have a rescue hoist motor (410) and a rescue hoist gear box (420) for transferring power from the rescue hoist motor (410) to the rescue traction mechanism (430). The rescue hoist (400) may utilize an electric, pneumatic, or hydraulic powered rescue hoist motor (410), such as any one of the hoists available via Sky Climber, LLC. of Stone Mountain, Ga. The rescue traction mechanism (430) is designed to grip the platform rope (300) and may be of the solid sheave type. Further, in an embodiment of the rescue hoist (402), the rescue hoist gear box (420) is a planetary and worm gear system designed to reduce the rotational speed of the rescue hoist motor (410) to a usable speed. One with skill in the art will appreciate that other gear systems may be incorporated in the rescue hoist gear box (420). Unlike the work hoist (200), however, the rescue hoist (402) is stationary and moves the platform rope (300) to raise and lower the work platform (300). Similar to the work hoist control system (700) and worker input device (710), in an embodiment of the instant invention, the system (50) has a rescue hoist control system (800) having a rescuer input device (810).

Referring now generally to FIGS. 4 and 5, in an embodiment of the instant invention, the rescue hoist control system (800) is in operative communication with the rescue hoist (402) and the work hoist (200), best seen in FIG. 5. In addition, the rescuer input device (810) controls the rescue hoist motor (410) to extend and retract the platform rope (300). Furthermore, in another embodiment of the instant invention, the rescuer input device (810) includes a stop button (812) and a directional control button (814), seen in FIG. 4. The stop button (812), as seen in FIG. 5, disconnects the rescue hoist motor (410) from an input power supply (900). Thus, the rescue hoist (402) is inoperable when the stop button (812) is engaged. While the directional control button (814) operates to ultimately provide power to the rescue hoist (402), the directional control button (814) also disengages the rescue traction brake (440) from the rescue traction mechanism (430). By way of example only, where the rescue hoist motor (410) is electrically powered, the rescue traction brake (440) may be an electromagnetic brake. In some applications, the rescue hoist control system (800) includes a pendant so that the rescuer does not need to be located at the rescue hoist control system (800) to control the movement of the work platform (100). In other words, the rescuer input device (810) may be at least one control switch, button, or toggle located on a fixed central control box or it may be all, or some, of those same devices located on a movable pendent. In contrast with FIG. 4, which shows the rescue hoist (402) with the rescue hoist control system (800) oriented in one direction, in another embodiment, the rescue hoist (402) may be an inverted work hoist. In other words, the rescue hoist (402) may be a work hoist hung upside down from the tie-off point (20). In the upside down orientation, the rescue hoist control system (800) would also be upside down.

In one embodiment, as seen in FIG. 5, the directional control button (814) is configured as two buttons, one for retracting the platform rope (300) and the other for extending the platform rope (300). By pressing one of the buttons, the rescue traction brake (440) first releases the rescue traction mechanism (430) while nearly simultaneously causing the rescue motor (410) to rotate. Once the button is released, the rescue traction brake (440) re-engages the rescue traction mechanism (430) substantially preventing unintentional rotation of the rescue traction mechanism (430). By way of example, and not limitation, the rescuer input device (810) may be a remote control pendent separate from the rescue hoist control system (800) but in wireless communication with the rescue hoist control system (800).

In an embodiment of the instant invention, with continued reference to FIGS. 4 and 5, the rescue hoist control system (800) further includes a work hoist lockout (820) for disconnecting the work hoist (200) from the input power supply (900), thus making the work hoist (200) inoperable when the work hoist lockout (820) is engaged. In yet another embodiment of the instant invention, the rescue hoist control system (800) includes a power supply tag-out mechanism (830). The power supply tag-out mechanism (830) disconnects both the rescue hoist motor (410) and the rescuer input device (810) from power until the rescuer operates the power supply tag-out mechanism (830) to reconnect power. Power means any man-made energy that causes motion. For example, power may include electricity, pressurized gas, and pressurized fluid. In one particular embodiment, the power supply tag-out mechanism (830) is highly visible, such that just about any rescuer will be able to quickly identify what it is and be able operate it.

In an embodiment of the instant invention, as seen in FIG. 5, the operation of a button or toggle transfers power between the rescue hoist (402) and the work hoist (200). As one skilled in the art will observe, there are many methods for constructing the rescue hoist control system (800) to alternate the input power supply (900) between the rescue hoist (402) and the work hoist (200) or, in other words, engaging the power supply tag-out mechanism (830) to connect the rescue hoist (402) to the input power supply (900) while engaging the work hoist lockout (820) to disconnect the work hoist (200) from the input power supply (900). While FIG. 5 illustrates the work hoist lockout (820) which operates to alternate power between input power supply (900) and the rescue hoist (402) and the work hoist (200), by way of example and not limitation, separate switches, relays, transistors, solenoid valves, and shutoff valves may be used.

Multiple safeties prevent inadvertent and premature operation of the rescue hoist (402). The redundant safety features require intentional intervention on the part of the rescuer, but can be completed quickly to bring the system (50) to operational status to perform rescues.

With reference once again to FIG. 2, in another embodiment of the instant invention, the structure (10) has a wall (12) with an interior surface (14) and an exterior surface (16). An access port (18) extends from the interior surface (14) to the exterior surface (16). Unlike the structure (10) in FIG. 1, a portion of the structure (10) in FIG. 2, resides between the rescue hoist (402) and the work platform (100). The platform rope (300) extends from the rescue hoist (402) through the access port (18) to the work platform (100). As one skill in the art will observe, the structure (10) may be a boiler or other pressure vessel which is enclosed. As previously mentioned, workers usually require access to the interior surfaces of such vessels. Access to the interior surfaces is typically through a small hatch, and in many cases the hatch is approximately eighteen inches in diameter, just large enough for an adult to climb through. Working on the interior of such vessels poses dangers in addition to those dangers associated with working on the exterior of buildings. Because of these dangers, the Occupational Health and Safety Administration (OSHA) has defined special precautions for entering these vessels, which OSHA has termed “confined spaces.” Limited access to the interior surfaces of confined spaces, such as boilers, also creates additional constraints on the size of the suspension equipment. For instance, it is often desirable to have a very compact work hoist (200) so that it may fit through the small opening into the confined space. Therefore, in one embodiment, seen in FIG. 2, the work platform (100) and each work hoist (200) are configured to pass through an eighteen inch diameter opening.

As seen in FIG. 2, the rescue hoists (402) are attached to the tie-off point (20) located outside the structure (10), and the work hoists (200) are located inside the structure (10). In day-to-day operation, the worker operates the worker input device (710) to raise and lower the work platform (100) by the work hoist (300) climbing up and down the stationary platform rope (300). In an emergency situation that leaves the worker stranded on the work platform (100), the rescuer operates the rescue hoist (402), as before, to raise or lower the work platform (100) by extending or retracting the platform rope (300). However, the position of the rescue hoist (402) and, particularly, the rescuer input device (810), as seen in FIG. 2, permits the rescuer to access the rescuer input device (810) and operate the rescue hoist (402) in safety, no entry into the confined space is necessary. The rescuer is not exposed to any dangerous conditions found inside the structure (10) while the rescuer lowers the worker to safety. Therefore, the rescuer avoids succumbing to any dangerous gases or liquids by remaining outside the structure (10). The work platform (100) may be lowered to the fall surface (30) so that the worker may exit the work platform (100) or receive immediate attention by other emergency response personnel. As one skilled in the art will observe, some industrial vessels may have access doors or maintenance passageways near the highest working elevation (110) which may also be used as a safety egress point for the worker.

In another embodiment of the instant invention, as seen in FIGS. 1 and 2, the system (50) includes an independent fall arrest system (600). The independent fall arrest system (600) is a safety system that prevents the worker from falling to the fall surface (30) following catastrophic failure of another component of the system (50) or due to a misstep on the work platform (100). In one embodiment, the independent fall arrest system (600) has a fall arrest rope (610), a fall arrest device (620), and a descent control system (630). Other fall arrest components may also be used as well. By way of example, and not limitation, other fall arrest components may include a body harness, a shock absorbing lanyard, a rope grab, and a rappel rack. The fall arrest rope (610) has a worker attachment portion (612) fastened to the worker, via the harness and the lanyard, and a tie-off point attachment portion (614) seen only in FIG. 2. The tie-off point attachment portion (614) may be an anchoring or securing system for reliably attaching the fall arrest rope (610) to the tie-off point (20). Similar to the platform rope (300), the fall arrest rope (610) has a fall arrest rope length. The fall arrest device (620) stores enough of the fall arrest rope (610) to extend to the fall surface (30). The descent control system (630) may be used to allow the rescuer to controllably release the fall arrest rope (610) to lower the worker. In one embodiment, the descent control system (630) may be incorporated in the fall arrest device (620), as seen only in FIG. 2. Thus, if the platform rope (300) fails and causes the work platform (100) to drop or otherwise become unusable, the descent control system (630) may be used to lower the worker to safety.

As previously mentioned, typically, during day-to-day operation of the system, the rescue device (400) is not used. Therefore, during day-to-day operation of the work hoist (200), the rescue device (400) locks the platform rope (300) in position so that the work hoist (200) may ascend and descend along a fixed platform rope (300). During day-to-day operation then, the rescue traction brake (440) is engaged, as is the rescue over-speed brake (450), to fix the platform rope (300) in position. In the event that an emergency occurs, where the work hoist (200) becomes disabled such that the work hoist (200) will not raise or lower the worker, the rescue device (400) is used to rescue the worker. Referring to FIGS. 1 and 6, the rescuer accesses the rescue device (400) which may, for example, be located on top of a building attached to the top side rigging. In one embodiment, the method of rescuing a worker involves raising or lowering the stranded worker by (a) resetting the rescue over-speed brake (450), (b) disengaging the rescue traction brake (440), and either (c) manipulating the lever on the rescue device (400) to raise the worker to the top of the building, or (d) operating a rescue controlled descent device (460) to lower the worker to the fall surface (30). Similarly, if the worker is disabled or is mentally or physically unable to operate the worker input device (710), the rescuer may again raise or lower the work platform (100) by resetting the rescue over-speed brake (450), disengaging the rescue traction brake (440), and raising or lowering the stranded worker to safety.

As with the rescue device (400), during non-emergency operation of the system (50) having the rescue hoist (402), as seen in FIG. 2, the rescue hoist (402) locks the platform rope (300) in position so that the work hoist (200) can ascend and descend along the platform rope (300) that is fixed in position. However, in an emergency where the worker becomes disabled, the rescuer would access the rescue hoist control system (800) to enable the rescue hoist (400) to raise or lower the stranded worker. By way of example and not limitation, in one embodiment of the instant invention, with reference to FIGS. 2 and 5, if the worker is incapacitated or is physically or mentally unable to operate the work hoist (200), the method of rescuing the worker is as follows. The rescuer will prepare the system (50) for rescue by (a) engaging the work hoist lockout (820) to lockout the work hoist (200), (b) engaging the power supply tag-out mechanism (830) to allow the rescue hoist control system (800) and the rescue hoist (402) to receive power, (c) resetting the rescue over-speed brake (450), and (d) disengaging the stop button (812). At this point, the rescue hoist (402) is operational. The rescuer can then operate the rescue hoist (402) by (e) operating the directional control button (814) which disengages the rescue traction brake (440) prior to causing the rescue motor (410) to rotate, or by (f) operating the rescue controlled descent device (460). The presence of multiple, complete safety devices, such as the rescue over-speed brake (450), the stop button (812), coupling the operation of the directional control button (814) to the rescue traction brake (440), the work hoist lockout (820), and the power supply tag-out mechanism (830), where each safety device completely disables the rescue hoist (402), helps prevent inadvertent activation of the rescue hoist (402) while the worker operates the work hoist (200).

In one embodiment of the instant invention, as previously discussed, there are multiple redundant safeties, such as, the stop button (812), the work hoist lockout (820), and the power supply tag-out mechanism (830). However, the rescuer is able to quickly reset the safeties to operate the rescue device (400). In one embodiment a descent rate of the work platform (100) is approximately thirty-five feet per minute, which is a maximum rate currently permitted by OSHA. However, one skilled in the art will recognize that higher rates are possible with government regulation being a limiting factor. One skilled in the art will appreciate the need for a rapid rescue when a stranded worker has been injured, particularly when the injuries are life threatening. For example, if the worker has a heart attack, passes out due to a lack of adequate oxygen, is lacerated causing a rapid blood loss, or sustains a head injury, immediate medical attention is necessary. In other words, in situations where time is of the essence. If the rescuer has to rig the rescue system prior to making the rescue, the worker may not survive. With the suspended work platform with an integrated rescue system (50), the rescuer can immediately bring the worker to safety and begin administering first aid. As one skilled in the art will observe, in another situation where the worker is rendered unconscious due to lack of oxygen, the worker may die in as little as four to six minutes. In another embodiment of the instant invention, the system (50) allows the rescuer to rescue the worker in less than four minutes.

In another, more dire, situation, the platform rope (300) catastrophically fails, leaving the worker suspended by the independent fall arrest system (600). The rescuer may lower the worker by operating the fall arrest device (620) to controllably release the fall arrest rope (610). Similar to the platform rope (300), the fall arrest rope (610) has sufficient length to allow a worker stranded near the rescue device (400), or rescue hoist (402), to be lowered to the fall surface (30) by the rescuer operating the fall arrest device (620).

Numerous alterations, modifications, and variations of the preferred embodiments disclosed herein will be apparent to those skilled in the art and they are all anticipated and contemplated to be within the spirit and scope of the instant invention. For example, although specific embodiments have been described in detail, those with skill in the art will understand that the preceding embodiments and variations can be modified to incorporate various types of substitute and or additional or alternative materials, relative arrangement of elements, and dimensional configurations. Accordingly, even though only few variations of the present invention are described herein, it is to be understood that the practice of such additional modifications and variations and the equivalents thereof, are within the spirit and scope of the invention as defined in the following claims. The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed. 

1. A suspended work platform with an integrated rescue system (50) for rescuing a worker on a work platform (100) suspended from a tie-off point (20) on a structure (10) wherein the tie-off point (20) is above the work platform (100) and a fall surface (30) is below the work platform (100), comprising: (A) a platform rope (300) having a maximum extension length; (B) a work hoist (200) having a work hoist motor (210), a work hoist traction mechanism (230) designed to cooperate with the platform rope (300), and a work hoist gear box (220) for transferring power from the work hoist motor (210) to the work hoist traction mechanism (230), wherein the work hoist (200) is attached to the work platform (100); (C) a work hoist control system (700) having a worker input device (710) accessible from the work platform (100), wherein the worker input device (710) is in operative communication with the work hoist (200), the worker input device (710), and the worker input device (710) controls the work hoist motor (210) such that the work hoist (200) ascends and descends along the platform rope (300); and (D) a rescue device (400) having a rescue traction mechanism (430) designed to cooperate with the platform rope (300), wherein the rescue device (400) is attached to the tie-off point (20), the rescue device (400) is operated at the tie-off point (20), the platform rope (300) extends downward from the rescue device (400) to suspend the work platform (100) by the work hoist (200), and the rescue device (400) controllably lowers the platform rope (300) and the work platform (100) to near the fall surface (30) before the maximum extension length of the platform rope (300) is reached.
 2. The suspended work platform with an integrated rescue system (50) of claim 1, wherein the work platform (100) travels on the platform rope (300) between a highest working elevation (110) and a fall surface exit elevation (120), thereby defining a working elevation range (130), wherein the highest working elevation (110) is the elevation at which the work hoist (200) nears the rescue device (400) and is prevented from ascending further towards the rescue device (400), the fall surface exit elevation (120) is the elevation at which the work platform (100) cannot be lowered any further, and the working elevation range (130) is the difference between the highest working elevation (110) and the fall surface exit elevation (120), wherein the maximum extension length of the platform rope (300) is at least approximately one hundred and fifty percent of the working elevation range (130) of the work platform (100).
 3. The suspended work platform with an integrated rescue system (50) of claim 1, wherein the work platform (100) travels on the platform rope (300) between a highest working elevation (110) and a fall surface exit elevation (120), thereby defining a working elevation range (130), wherein the highest working elevation (110) is the elevation at which the work hoist (200) nears the rescue device (400) and is prevented from ascending further towards the rescue device (400), the fall surface exit elevation (120) is the elevation at which the work platform (100) cannot be lowered any further, and the working elevation range (130) is the difference between the highest working elevation (110) and the fall surface exit elevation (120), wherein the maximum extension length of the platform rope (300) is at least approximately one hundred and ninety percent of the working elevation range (130) of the work platform (100).
 4. The suspended work platform with an integrated rescue system (50) of claim 1, wherein the rescue device (400) has a rescue traction brake (440) designed to engage the rescue traction mechanism (430), a rescue over-speed brake (450) for stopping uncontrolled passage of the platform rope (300) through the rescue device (400), and a rescue controlled descent device (460) that releases the rescue traction brake (440) allowing controlled withdrawal of the platform rope (300) through the rescue device (400).
 5. The suspended work platform with an integrated rescue system (50) of claim 1, wherein the work hoist (200) further includes a work hoist controlled descent device (260) for controlling the non-powered passage of the platform rope (300) through the work hoist (200) allowing the work platform (100) to descend by gravity along the platform rope (300).
 6. The suspended work platform with an integrated rescue system (50) of claim 4, wherein the rescue device (400) is a rescue hoist (402) having a rescue hoist motor (410) and a rescue hoist gear box (420) for transferring power from the rescue hoist motor (410) to the rescue traction mechanism (430), and further including a rescue hoist control system (800) having a rescuer input device (810), wherein the rescue hoist control system (800) is in operative communication with the rescue hoist (402) and the work hoist (200) and the rescuer input device (810) controls the rescue hoist motor (410) to extend and retract the platform rope (300).
 7. The suspended work platform with an integrated rescue system (50) of claim 6, wherein the rescuer input device (810) further includes a stop button (812), wherein the stop button (812) disconnects the rescue hoist motor (410) from power, whereby the rescue hoist (402) is inoperable when the stop button (812) is engaged.
 8. The suspended work platform with an integrated rescue system (50) of claim 5, wherein the rescue hoist control system (800) further includes a work hoist lockout (820), wherein the work hoist lockout (820) disconnects the work hoist (200) from power, whereby the work hoist (200) is inoperable when the work hoist lockout (820) is engaged.
 9. The suspended work platform with an integrated rescue system (50) of claim 5, wherein the rescue hoist control system (800) further includes a power supply tag-out mechanism (830), wherein the power supply tag-out mechanism (830) disconnects the rescue hoist motor (410) and the rescuer input device (810) from power until the rescuer operates the power supply tag-out mechanism (830) to reconnect power.
 10. The suspended work platform with an integrated rescue system (50) of claim 5, the rescuer input device (810) further includes a directional control button (814), wherein the rescue traction brake (440) releasably engages the rescue traction mechanism (430) and the directional control button (814) is in operative communication with the rescue traction brake (440) and the rescue hoist motor (410), whereby when the directional control button (814) is operated the rescue traction brake (440) releases the rescue traction mechanism (430) and causes the rescue hoist motor (410) to rotate.
 11. The suspended work platform with an integrated rescue system (50) of claim 1, further including an independent fall arrest system (600) having a fall arrest rope (610) and a fall arrest device (620), wherein the fall arrest rope (610) has a worker attachment portion (612) fastened to the worker and a tie-off point attachment portion (614) attached to the tie-off point (20), whereby when the worker is suspended by the independent fall arrest system (600), the rescuer lowers the worker by operating the fall arrest device (620) to controllably extend the fall arrest rope (610) under the influence of gravity.
 12. The suspended work platform with an integrated rescue system (50) of claim 5, wherein the rescuer input device (810) is accessible near the tie-off point (20).
 13. The suspended work platform with an integrated rescue system (50) of claim 5, wherein the rescuer input device (810) is not accessible from the work platform (100).
 14. A suspended work platform with an integrated rescue system (50) for rescuing a worker on a work platform (100) having a highest working elevation (110), a fall surface exit elevation (120), and a working elevation range (130) and the work platform (100) is suspended from a tie-off point (20) on a structure (10) having a wall (12) with an interior surface (14) and an exterior surface (16), and an access port (18) extending from the interior surface (14) to the exterior surface (16), wherein the tie-off point (20) is outside the structure (10) and the work platform (100) is inside the structure (10) with a fall surface (30) below the work platform (100), comprising: (A) a platform rope (300) having a maximum extension length; (B) a work hoist (200) having a work hoist motor (210), a work hoist traction mechanism (230) designed to cooperate with the platform rope (300), a work hoist gear box (220) for transferring power from the work hoist motor (210) to the work hoist traction mechanism (230), and a work hoist controlled descent device (260) for controlling the non-powered passage of the platform rope (300) through the work hoist (200), wherein the work hoist (200) is attached to the work platform (100) and operation of the work hoist controlled descent device (260) allows the work platform (100) to descend by gravity along the platform rope (300) to the fall surface exit elevation (120) where the work platform (100) cannot be lowered any further; (C) a work hoist control system (700) having a worker input device (710) accessible from the work platform (100), the work hoist control system (700) is in operative communication with the worker input device (710) and the work hoist (200), wherein the worker input device (710) controls the work hoist motor (210) such that the work hoist (200) ascends and descends along the platform rope (300); (D) a rescue hoist (402) attached to the tie-off point (20), the rescue hoist (402) having a rescue hoist motor (410) and a rescue hoist gear box (420) for transferring power from the rescue hoist motor (410), a rescue traction mechanism (430) designed to cooperate with the platform rope (300), a rescue traction brake (440) designed to engage the rescue traction mechanism (430), a rescue over-speed brake (450) for stopping uncontrolled passage of the platform rope (300) through the rescue hoist (402), and a rescue controlled descent device (460) that releases the rescue traction brake (440) allowing controlled withdraw of the platform rope (300) through the rescue hoist (402), wherein (i) the platform rope (300) extends downward from the rescue hoist (402) through the access port (18) to suspend the work platform (100) by the work hoist (200), (ii) the work platform (100) travels on the platform rope (300) between a highest working elevation (110) and a fall surface elevation (120), thereby defining a working elevation range (130), and (iii) the maximum extension length of the platform rope (300) is at least approximately one hundred and fifty percent of the working elevation range (130) of the work platform (100); (E) a rescue hoist control system (800) in operative communication with the rescue hoist (402) and the work hoist (200), the rescue hoist control system (800) having a rescuer input device (810), a work hoist lockout (820), and a power supply tag-out mechanism (830), wherein (i) the rescuer input device (810) is in operative communication with the rescue traction brake (440) and the rescue hoist motor (410); (ii) the rescuer input device (810) has a stop button (812) and a directional control button (814), wherein (a) the stop button (812) disconnects the rescue hoist motor (410) from power, whereby the rescue hoist (402) is inoperable when the stop button (812) is engaged; and (b) the directional control button (814) causes the rescue traction brake (440) to disengage from the rescue traction mechanism (430) while causing the rescue hoist motor (410) to extend or retract the platform rope (300); and (iii) the work hoist lockout (820) disconnects the work hoist (200) from power, whereby the work hoist (200) is inoperable when the work hoist lockout (820) is engaged; and (F) an independent fall arrest system (600) having a fall arrest rope (610) formed with a worker attachment portion (612) and a tie-off point attachment portion (614), wherein the worker attachment portion (612) is fastened to the worker, the fall arrest rope (610) extends through the access port (18), and the tie-off point attachment portion (614) of the fall arrest rope (610) engages a fall arrest device (620) and is attached to the tie-off point (20), such that the independent fall arrest system (600) suspends the worker, and the fall arrest device (620) allows controlled withdraw of the fall arrest rope (610) to lower the worker to the fall surface (30).
 15. The suspended work platform with an integrated rescue system (50) of claim 14, wherein the rescuer input device (810) is accessible near the tie-off point (20) and the rescuer input device (810) is outside the structure (10).
 16. The suspended work platform with an integrated rescue system (50) of claim 14, wherein the rescuer input device (810) is not accessible from the work platform (100).
 17. The suspended work platform with an integrated rescue system (50) of claim 14, wherein the power supply tag-out mechanism (830) disconnects the rescue hoist motor (410) and the rescuer input device (810) from power until the rescuer operates the power supply tag-out mechanism (830) to reconnect power.
 18. A method for rescuing a worker from an elevated position, comprising: moving a work platform (100), wherein a rescuer operates a rescue hoist (402), the rescue hoist (402) is connected to a tie-off point (20), the rescue hoist (402) has a rescue hoist motor (410) and a rescue hoist gear box (420) for transferring power from the rescue hoist motor (410) to the rescue traction mechanism (430), the rescue hoist (402) extends and retracts a platform rope (300), the platform rope (300) is engaged by a work hoist (200), and the work hoist (200) is attached to the work platform (100), and wherein the rescuer operates the rescue hoist (402) by (i) resetting a stop button (812), wherein the stop button (812) prevents the rescue hoist (402) from receiving power until the rescuer resets the stop button (812); (ii) deactivating a rescue over-speed brake (450), wherein the rescue over-speed brake (450) prevents downward motion of the platform rope (300) while engaged, and once deactivated the rescue over-speed brake (450) prevents uncontrolled withdraw of the platform rope (300) through the rescue hoist (402); (iii) disengaging a power supply tag-out mechanism (830), wherein the power supply tag-out mechanism (830) prevents the rescue hoist (402) from operating while engaged; and (iv) operating a directional control button (814) which causes a rescue traction brake (440) to releasably disengage a rescue traction mechanism (430) which allows the rescue hoist (402) to move the work platform (100) and the worker.
 19. The method for rescuing the worker of claim 18, further including the step of: activating a work hoist lockout (820) following the resetting of the stop button (812), wherein the work hoist lockout (820) prevents the work hoist (200) from operating.
 20. The method for rescuing the worker of claim 18, wherein when the rescuer operates the rescue hoist (402), the work platform (100) moves from a highest working elevation (110) to a fall surface exit elevation (120) at a rate of approximately 35 feet per minute, wherein the highest working elevation (110) is the elevation at which the work hoist (200) is near the rescue hoist (402) and is prevented from ascending further towards the rescue hoist (402), and the fall surface exit elevation (120) is the elevation at which the work platform (100) cannot be lowered any further. 